Marie-Odile Husson

Natural outcome of Helicobacter pylori infection in asymptomatic children: a two-year follow-up study.

Background and Objectives. It is known that Helicobacter pylori can be acquired in early childhood. There is not enough data to know whether or not infected children should be treated. A better knowledge of the natural outcome and implications of H pylori infection may provide evidence that eradication therapy is beneficial in childhood. This prospective study looks at clinical symptoms, endoscopic, microbial, and histologic changes during a 2-year period in infected asymptomatic children. It is hoped that some prognostic indicators will be found that select out the children that later need therapy. Patients and Methods. During epidemiologic study of the prevalence of H pylori infection, 18 children aged 7 ± 4 years (mean ± 1 SD) were discovered to have H pylori infection and enrolled in the 2-year follow-up study. These patients had received no eradication therapy because they were asymptomatic. The follow-up for each patient consisted of an initial assessment, a clinical examination every 6 months, and an endoscopic reevaluation at the end of the first and second years. Gastric mucosal samples were analyzed for bacteriologic and histologic changes. Various factors were initially recorded: individual factors included sex, age, and housing conditions; microbial factors included bacterial load and the presence of the CagA gene. Inflammatory changes were also noted, such as the presence of active gastritis and nodular formation, and these were correlated with the histology which was described using the Sydney classification. Typing polymerase chain reaction-restriction fragment length polymorphism was performed to check the persistence of the same strain of H pyloriin each patient. Results. All of the children were still infected after 2 years with the same strain as in the initial assessment with the exception of 1 child whose infection cleared spontaneously. The density of antral and fundal mucosal colonization with H pylorialso remained stable. There were progressive inflammatory changes in this cohort, particularly between the first and second year (histologic score, 3.5 ± 1.3 vs 5 ± 1). Active antral gastritis occurred in 3 out of 14 and 1 out of 8 children during the first and second year, respectively. Gastritis became active in the fundus in 2 out of 14 and 2 out of 8 children during the same period. Increases in the histologic score were found particularly in male children, and children colonized by cagA− strains of H pylori during the follow-up. The frequency of nodular gastritis significantly rose from 11% (2 out of 18 children) to 64% (9 out of 14 children) after 1 year, and to 80% (8 out of 10 children) after 2 years. Conclusion. These findings demonstrate a deterioration in the histologic features of the gastric mucosa of infected children despite stable H pylori colonization and the absence of symptoms.

Dietary (n-3) Polyunsaturated Fatty Acids Affect the Kinetics of Pro- and Antiinflammatory Responses in Mice with Pseudomonas aeruginosa Lung Infection

The underlying mechanisms by which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) affect host resistance to Pseudomonas aeruginosa are unclear. The aim of this study was to determine their role on the kinetic of pro- and antiinflammatory response in lung infection. Mice fed either a control diet or a diet enriched with EPA and DHA were infected intratracheally and we studied lung expression of proinflammatory markers [CXCL1, interleukin (IL)-6, tumor necrosis factor-alpha], antiinflammatory markers (IL-10, A20, and IkappaB alpha), and PPARalpha and PPARgamma. The inflammatory response was assessed using recruitment of neutrophils and macrophages into bronchoalveolar lavage fluid, bacterial clearance from the lung, pulmonary injury, and 7-d survival rate. Compared with the control group, EPA and DHA delayed the expression of proinflammatory markers during the first 2 h (P < 0.05), upregulated proinflammatory marker expression (P < 0.05), and induced overexpression of antiinflammatory markers at 8 h (P < 0.05), enhanced recruitment of neutrophils at 16 h (P < 0.05), and induced PPARalpha and PPARgamma overexpression at 4 and 8 h (P < 0.01), respectively. Pulmonary bacterial load decreased and pulmonary injury and mortality were reduced during the first 24 h (P < 0.05). In conclusion, EPA and DHA modulate the balance between pro- and antiinflammatory cytokines, alter the early response of the host to P. aeruginosa infection, and affect the early outcome of infection.

Clinical and microbiological features of Inquilinus sp. isolates from five patients with cystic fibrosis.

ABSTRACT Patients with cystic fibrosis (CF) may be colonized with unusual gram-negative bacilli whose identification is difficult and clinical impact unclear. We describe the clinical and microbiological features of five colonizations with organisms belonging to the recently described genus Inquilinus in CF patients. Isolates were identified from Burkholderia cepacia selective medium by means of 16S rRNA analysis. All of them were resistant to colistin, penicillins, cephalosporins, and monobactams but exhibited a remarkable susceptibility to imipenem. One of the five patients was transiently colonized with a nonmucoid isolate, whereas the four other patients were persistently colonized over the period of follow-up (8 to 21 months) with mucoid isolates. Pulsed-field gel electrophoresis of SpeI-digested genomic DNA was powerful for strain genotyping and demonstrated the clonality of Inquilinus sp. colonization for the two patients tested. Clinical evolution after the onset of Inquilinus was heterogeneous, but for at least one patient the lung function worsened and eradication of Inquilinus sp. was unsuccessful despite several imipenem courses. Finally, Inquilinus spp. may represent a new threat for CF patients due to their mucoid characteristic, their multiresistant pattern to antibiotics, and their ability to persist in the respiratory tract.

Dietary n-3 fatty acids have suppressive effects on mucin upregulation in mice infected with Pseudomonas aeruginosa.

BackgroundMucin hypersecretion and mucus plugging in the airways are characteristic features of chronic respiratory diseases like cystic fibrosis (CF) and contribute to morbidity and mortality. In CF, Pseudomonas aeruginosa superinfections in the lung exacerbate inflammation and alter mucus properties. There is increasing evidence that n-3 polyunsaturated fatty acids (PUFAs) exhibit anti-inflammatory properties in many inflammatory diseases while n-6 PUFA arachidonic acid (AA) favors inflammatory mediators such as eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) that may enhance inflammatory reactions. This suggests that n-3 PUFAs may have a protective effect against mucus over-production in airway diseases. Therefore, we hypothesized that n-3 PUFAs may downregulate mucins expression.MethodsWe designed an absolute real-time PCR assay to assess the effect of a 5-week diet enriched either with n-3 or n-6 PUFAs on the expression of large mucins in the lungs of mice infected by P. aeruginosa.ResultsDietary fatty acids did not influence mucin gene expression in healthy mice. Lung infection induced an increase of the secreted gel-forming mucin Muc5b and a decrease of the membrane bound mucin Muc4. These deregulations are modulated by dietary fatty acids with a suppressive effect of n-3 PUFAs on mucin (increase of Muc5b from 19-fold up to 3.6 × 105-fold for the n-3 PUFAs treated group and the control groups, respectively, 4 days post-infection and decrease of Muc4 from 15-fold up to 3.2 × 104-fold for the control and the n-3 PUFAs treated groups, respectively, 4 days post-infection).ConclusionOur data suggest that n-3 PUFAs enriched diet represents an inexpensive strategy to prevent or treat mucin overproduction in pulmonary bacterial colonization.

(n-3) Long-Chain PUFA Differentially Affect Resistance to Pseudomonas aeruginosa Infection of Male and Female cftr–/– Mice

The aim of this study was to determine whether oral supplementation with EPA/DHA (10.5 and 5.1% of fat, respectively) could improve the outcome of pulmonary P. aeruginosa infection in cftr(-/-) mice compared with wild-type (Wt) mice similarly treated. Because gender could influence the susceptibility of cftr-deficient mice, results were analyzed by gender. Wt and (-/-) mice were randomized for 6 wk to consume a control or EPA/DHA diet, infected with endotracheal injection of 5 × 10(7) CFU/mouse of P. aeruginosa, and killed 24 h later. Cftr(-/-) mice were more susceptible to infection than were Wt mice; (-/-) males had more neutrophils (P < 0.01) and a higher keratinocyte-derived chemokine (KC) level (P < 0.05), and (-/-) females had greater lung injury and mortality (P < 0.05). Female (-/-) mice were more susceptible than (-/-) males with a higher mortality and lung injury (P < 0.05). The EPA/DHA diet reduced neutrophil numbers and KC and IL-6 levels (P < 0.05) in (-/-) males and reduced mortality rate (P < 0.001), lung permeability, and IL-6 level (P < 0.05) in (-/-) females compared with (-/-) mice fed the control diet. These results were associated with a reduction in the pulmonary bacterial load (P < 0.05), an increase in the EPA/DHA concentration in cell membranes of (-/-) males and females (P < 0.01), and an increased weight gain only in males compared with (-/-) mice fed the control diet (P < 0.01). In conclusion, EPA/DHA improves the host resistance of (-/-) mice, although the beneficial effect differed in males and females.

Dietary Pectin–Derived Acidic Oligosaccharides Improve the Pulmonary Bacterial Clearance of Pseudomonas aeruginosa Lung Infection in Mice by Modulating Intestinal Microbiota and Immunity

BACKGROUND A predominantly T-helper type 2 (Th2) immune response is critical in the prognosis of pulmonary Pseudomonas aeruginosa infection. But the mucosal and systemic immune responses can be influenced by the intestinal microbiota. METHODS We assessed the effect of microbiota compositional changes induced by a diet enriched in 5% acidic oligosaccharides derived from pectin (pAOS) on the immune response and outcome of chronic pulmonary P. aeruginosa infection in mice. RESULTS pAOS promoted Th1 polarization by increasing interferon γ release, upregulating t-bet gene expression, decreasing interleukin 4 secretion, and downregulating gata3 gene expression. pAOS also sustained the release of keratinocyte chemoattractant, recruited polynuclear leukocytes and macrophages, stimulated M1 macrophage activation and interleukin 10 release, and decreased tumor necrosis factor α release in the lung. These effects led to increased bacterial clearance after the first and second P. aeruginosa infections. pAOS modified the intestinal microbiota by stimulating the growth of species involved in immunity development, such as Bifidobacterium species, Sutturella wadsworthia, and Clostridium cluster XIVa organisms, and at the same time increased the production of butyrate and propionate. CONCLUSION These results suggest that pAOS may have beneficial effects by limiting the number and severity of pulmonary exacerbations in patients chronically infected with P. aeruginosa, such as individuals with cystic fibrosis.

Direct antimicrobial susceptibility testing method for analysis of sputum collected from patients with cystic fibrosis.

BACKGROUND Chronic Pseudomonas aeruginosa colonisation and subsequent exacerbations in patients with cystic fibrosis (CF) require antimicrobial treatment. But since multiple morphotypes and other Gram-negative bacteria with different antibiotic susceptibilities are often isolated inside the same sputum sample, bacteriological analysis is difficult. METHODS To simplify this analysis, we explored a direct sputum antimicrobial susceptibility testing (DSST) method by applying E test directly on plates inoculated with the sputum. A total of 316 samples collected from CF patients were analysed and compared with standard procedures (SP) for the identification and antimicrobial susceptibility testing of all Gram-negative bacterial species. RESULTS DSST was as efficient as SP to detect P. aeruginosa including the mucoid morphotype in monomicrobial specimen, but was less sensible to detect all Gram-negative bacteria present in the same sample. It allowed the direct reading of the MIC inhibiting all Gram-negative bacteria. Agreements between these global MICs with the cumulative antibiotics susceptibility of all Gram-negative bacteria measured by SP were excellent for tobramycin and imipenem (>96%) and satisfactory for ticarcillin, ceftazidime, aztreonam and ciprofloxacin (90.4% to 94.3%). In conclusion, the DSST method is an efficient and easy antibiotic susceptibility testing method.

Long-Chain Polyunsaturated Fatty Acids Modulate Lung Inflammatory Response Induced by Pseudomonas aeruginosa in Mice

Polyunsaturated fatty acid (PUFA) immunomodulatory properties have been studied extensively in chronic infections. Few studies have focused on acute infection; thus, PUFA effects in a mouse model of Pseudomonas aeruginosa (PA)-induced lung injury were evaluated. C57BL/6 mice were randomized to be fed for 3 wk with an eicosapentaenoic acid (EPA) diet, an arachidonic acid (AA) diet, or a control diet [saturated fatty acids]. Lung injury was induced by intratracheal instillation of 107 CFU of PA per mouse. In each diet group, animals were studied either without or after PA–inducing lung injury. Evaluation criteria were early mortality; inflammatory response assessed with tumor necrosis factor-α (TNF-α), IL-1β, IL-6 and IL-10 levels in bronchoalveolar lavage; lung injury evaluation; and extravascular lung water, assessed 24 h after the injury. After PA-induced lung injury, no difference in early mortality was observed; TNF-α level was significantly higher in the EPA diet than in the other two diet groups. No difference for the other cytokines was found among the groups. Lung edema was also more important in the EPA group, consistent with the variations of TNF-α levels. Our study clearly shows that in PA-induced acute lung injury, n-3 PUFA induces differences in the inflammatory response with a higher level of lung edema. Modulation of the inflammatory response with n-3 PUFA can influence the response to a bacterial challenge.

Helicobacter pylori in Children: Acquisition of Antimicrobial Resistance after an Initial Course of Treatment

According to a recent consensus statement concerning Helicobacter pylori infection in children (3), upper gastrointestinal endoscopy with biopsies is the preferred method for establishing an etiologic diagnosis of infection. The treatment recently recommended for children combines a gastric acid inhibitor, usually a proton pump inhibitor (PPI), with two antimicrobial agents, an antimicrobial agent plus a bismuth salt, or two antimicrobial agents (4). In France, where the use of bismuth salts is not authorized, treatment consists of amoxicillin plus either clarithromycin or metronidazole. The consensus statement (3) also proposed a strategy for reevaluating those who remain infected after an initial course of therapy: repeat endoscopy with culture and antimicrobial susceptibility testing, with secondary treatment based on susceptibility test results.

Impact of fish oils on the outcomes of a mouse model of acute Pseudomonas aeruginosa pulmonary infection

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes pneumonia in immunocompromised humans and severe pulmonary damage in patients with cystic fibrosis. Imbalanced fatty acid incorporation in membranes, including increased arachidonic acid and decreased DHA concentrations, is known to play a critical role in chronic inflammation associated with bacterial infection. Other lipids, such as EPA and alkylglycerols, are also known to play a role in inflammation, particularly by stimulating the immune system, decreasing inflammation and inhibiting bacterial growth. In this context, the goal of the present study was to assess the effect of dietary DHA/EPA, in a 2:1 ratio, and alkylglycerols, as natural compounds extracted from oils of rays and chimeras, respectively, on the inflammatory reaction induced by P. aeruginosa pulmonary infection in mice. To this end, mice were fed with a control diet or isolipidic, isoenergetic diets prepared with oils enriched in DHA/EPA (2:1) or alkylglycerols for 5 weeks before the induction of acute P. aeruginosa lung infection by endotracheal instillation. In our model, DHA/EPA (2:1) significantly improved the survival of mice after infection, which was associated with the acceleration of bacterial clearance and the resolution of inflammation leading to the improvement of pulmonary injuries. By contrast, alkylglycerols did not affect the outcomes of P. aeruginosa infection. Our findings suggest that supplementation with ray oil enriched in DHA/EPA (2:1) can be considered as a preventive treatment for patients at risk for P. aeruginosa infection.